ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/6CN.Fe.4K/c6%2A1-2/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/6CN.Fe.4K/c6%2A1-2 could not be loaded.